Renal transplantation is the treatment of choice for managing patients with end-stage kidney disease. Being submitted to a very serious surgical procedure, renal transplant recipients can only benefit from follow-up imaging and monitoring strategies. Ultrasound is considered as the principal imaging test in the evaluation of renal transplants. It is an easily applied bedside examination that can detect possible complications and guide further imaging or intervention. In this imaging review, we present essential information regarding the sonographic features of healthy renal transplants, detailing the surgical technique and how it affects the sonoanatomy. We focus on various complications that occur following renal transplantation and their sonographic features by reviewing pertinent literature sources and our own extensive imaging archives. 1. Introduction Renal transplantation is considered a treatment of choice for end-stage kidney disease (ESKD) since the 1960s. It is cost-effective and provides better long-term survival and better life quality in comparison to hemodialysis and/or peritoneal dialysis [1]. With improved transplantation technology, new generations of immunosuppressive agents and developments in graft preservation techniques, the 1-year survival rates for grafts, are reported to be 80% for mismatched cadaveric renal grafts; 90% for nonidentical living related grafts; 95% for human lymphocyte antigen-identical grafts. The half-life of grafts from living related donors varies between 13 and 24 years, depending on the match [2]. Two-dimensional ultrasound (US) was introduced in the evaluation of renal transplants back in the 1970s, while the application of Doppler techniques in the following years established the method in routine practice. US is a relatively cheap, noninvasive, and nonnephrotoxic modality, which may be applied for diagnostic and monitoring purposes early on, in the posttransplant period, establishing thus a baseline for follow-up scanning. Its role in the evaluation of early graft complications is of paramount importance as besides detecting vascular pathology (i.e., arterial stenosis and venous thrombosis); it can be also utilized for guided renal biopsy and drainage of fluid collection [3–5]. Hereby, we present basic points of US evaluation in kidney transplantation. 2. Ultrasound Evaluation of the Healthy Renal Transplant A baseline US evaluation is performed in the first 24–48 hours posttransplantation. A detailed examination protocol includes renal size and echogenicity, collecting system and ureter condition and
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